System and method for controlling a stack pin in a weight stack of an exercise machine and for providing anatomically correct body movement on an exercise machine

ABSTRACT

A system for controlling a free end of a stack pin used with a stack of weights, the system including a nesting device configured to secure the free end of a stack pin when the stack pin is not lifting a weight and a tuning device configured to adjust the nesting device to exert a back up pressure on the stack pin to counteract potential energy that accumulates when the stack pin is being used to lift the weight.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Nos. 61/481,462 filed May 2, 2011; 61/505,627 filed Jul. 8, 2011; and 61/511,677 filed Jul. 26, 2011, and each incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

A selectorized weight stack has been used for several decades with respect to exercise machines and has been improved in various ways over the years. FIG. 1 depicts an illustration of a prior art selectorized weight stack. In its conventional form (in those designs whereby it is pulled from above rather than pushed from below), the selectorized weight stack has multiple plates 10, usually made of steel, in denominations of weight, usually uniform denominations. These plates 10 are optionally engaged by the user with the insertion of a horizontally-oriented selector pin 12 that is inserted to bridge between a respective plate 10 or a multiple of plates and a vertically-oriented stack pin 14 (illustrated in FIG. 2). FIG. 2 depicts an illustration of other prior art components of the selectorized weight stack. At its top end, the stack pin 14 is connected to force-transmitting connection 16 of the weight apparatus that works to lift the stack pin 14 and its load of weights 10 vertically. This lifting and reciprocal lowering of the weights 10 by the stack pin 14 is controlled along a pathway defined by guiderods 18.

Keeping the weight stack controlled along its guided path is often accomplished by a solid connection between the stack pin 14 and its corresponding top plate 11. The top plate 11 and its connection to the stack pin 14 can be designed to further control the upper end of the stack pin 14 and their unison travel along the guiderods 18. However, control of a lower end of the stack pin 14 in the prior art has been neglected. Poor control of the lower end of the stack pin 14 may result in several problems, generally associated with a large amount of horizontal force. This force is simultaneously leveraged to the top plate 11 and its guiderod controls 20 (bushings, bearings, etc.). If these guiderod controls 20 are properly and tightly designed as both to reduce friction and to prevent top-plate rocking, potential energy is stored in the length of the stack pin, which may be released in a “spring effect.” This spring effect can serve to undesirably walk the plates horizontally and choke the guiderods 18, thus, causing undesirable friction in the weight stack system. In view of these problems that exist currently, manufacturers and owners of such weight machines would benefit from a system and method that reduces experienced horizontal forces and the resulting undesirable friction that may result if the lower end of the stack pin is not effectively controlled.

Additionally, many exercise machines are built as “one-size-fits-all,” meaning that making adjustments to exercise machines to best accommodate a person's physique is usually limited. Usually, depending on the exercise machine, height adjustment is provided, either based on leg length or torso length, but that is usually the limitation of adjustments provided to accommodate anatomically diverse individuals or users. One such exercise machine that applies the one-size-fits-all approach in its design is usually a trunk extension exercise machine.

A trunk extension movement is a general posterior movement whereby the trunk and pelvis and hips of an individual rotate collectively. This differs from a more specific extension of the hip(s), pelvis, lumbar, or thoracic spine. The American Academy of Orthopedic Surgeons applies the term hyperextension to denote any movement or position beyond anatomical zero. Anatomical neutral or anatomical zero is defined as that position of the trunk permitting a straight line through shoulders, hips and knees as the human form is viewed laterally. Inconsistency with hyperextension arises both in technical context as well as in emotional interpretation.

If any position posterior to anatomical neutral is denoted as hyperextension, then any position anterior to anatomical neutral may be denoted as hyperflexion. Additionally, the prefix, hyper, suggests an extreme condition, and this, along with other myths, evokes hysteria regarding the design of exercises and exercise equipment for the trunk.

In the Applicant's opinion, based on independent research and evaluation, large exercise equipment companies such as Nautilus®, MedX®, and Cybex®, have a long history of marketing equipment to avoid active hyperextension of the trunk on their trunk extension or lumbar extension movements, but overlook the fact that their so-called abdominal designs passively push the trunk into hyperextension which results in a non-favorable positioning of the lumbar region of a body.

In the 1980's, Nautilus® Sport/Medical Industries sold a trunk extension machine dubbed a Lower Back machine. It incorporated a “dog” on its movement arm to delimit extensional movement beyond approximately anatomical neutral. Some versions of these products delimited the excursion somewhat more. This delimitation was incorporated, in part, to avoid condemnation from the medical community. FIG. 3 depicts a reengineered Nautilus® Lower Back (trunk extension) machine by SuperSlow® Systems, Inc. where a correct form is depicted showing the knees slightly flexed and the heels firmly planted on the pedestal. However, FIG. 4 depicts a user violating the positioning shown in FIG. 3 by both straightening the legs and coming off the heels (slightly rising off the heels). As illustrated, the heels are raised and the knees are straightened, pushing the buttocks over the back of the seat 22. This violation is allowed due to the design of the machine.

Since 1986, MedX Company has designed and marketed its Lumbar machines. Some of these were made for measurement and exercise and some merely for exercise. In the Applicant's view, these machines delimited extensional range to ˜50 degrees short of anatomical zero while increasing flexional range (compared to the Nautilus versions that preceded it) by ˜25 degrees. FIG. 5 depicts a representation of a prior art MedX® Lumbar machine. MedX® approaches the heel raising problem illustrated in FIG. 3 with a thigh constraint 24 that forces the heels down onto the pedestal 26. Note that this constraint does not curtail the subject's inappropriate volition, the effort to raise the heels, but merely blunts movement that would be powered by the volition. MedX® solves the leg-straightening problem by providing for an adjustable pressure 28 against the tibial tuberocities that transmits through the femurs and pelvis to blunt the posterior movement of the buttocks. Again, in the Applicant's opinion, this constraint does not curtail the subject's inappropriate volition, the effort to straighten the legs, but merely blunts movement that is powered by the volition.

While it is obvious that the MedX® approach has helped many with back issues, a major medical expense in today's society, it is also probable that many other back issues are better served with the deletion of most of the constraint and movement restrictions incorporated into the MedX® Lumbar. A form of exercises commonly known as William's Flexion Exercises (Paul C. Williams, M.D.) has been prescribed to many patients' back issues resulting in good results in this country since he described his exercises in 1937. Another form of exercises known as the McKensie Extension Exercises has been applied in New Zealand and Australia with yet better outcomes. However, inconsistency exists between the type forms of exercise since Dr. Williams preaches that trunk extension is the cause of many back complaints while McKensie shows that extension is the cure, especially of sciatica, as decompression of the intervertebral discs occurs as the facets are loaded and leveraged upon during extension. As McKensie demonstrated, flexion actually compresses the discs.

A yet more concerning back issue is spondylolythesis. With this condition the vertebral bodies can shift anterio-posteriorly with grave consequences. Observation shows that that extreme extension is relieving for many patients while extreme flexion actually increases instability and pain. Another looming issue that has not been addressed by any prior art inventions and/or disclosures is the issue of motion speed. Many potentially fruitful as well as worthless approaches to back problems have been evaluated in the context of fast movement speed. Without a controlled excursion speed like that of the SuperSlow® and RenEx® protocols (positive excursion in ten seconds, negative excursion in ten seconds) appropriate resistance curves cannot be effected, friction cannot be assessed, and injurious acceleration forces cannot be eliminated.

Additionally, isometric exercise is very valuable for many patients for whom movement is painful. However, the traditional approach to isometrics has been a contraction duration that is too short and too violent due to abrupt application. Favored is a staged duration of 90-120 seconds (termed Timed-Static Contraction) rather than the traditional 5-15 second duration of all-out maximum effort. Thus, an exercise machine is needed to address the shortcomings of current trunk extension exercise machines.

Exercise machines also exist to allow individuals to perform an exercise where the user grips a handle to experience resistance from weight applied to the handle. FIG. 6 is an illustration of such a prior art exercise machine, typically known as a pull down exercise machine. The pull down exercise involves having the individual's arms begin at a positive excursion, in preparation of lifting a weight, with elbows extended and shoulders flexed (in accordance with the American Society of Orthopaedic Surgeons' standard for anatomical nomenclature). When ready to lift the weight, the individual simultaneously flexes the elbows and extends their shoulders until the forearms are abutted to the upper chest.

In performing this exercise, the hands and wrists are expected to travel toward (not to) the upper chest and just medially to the anterior aspect of the shoulders, not directly to the shoulders and not lateral to the shoulders. Proper placement distance between the hands is permitted along the continuous grip 29 of the pictured handle 30. However, this handle 30, although angled as far as structurally possible, does not accommodate the necessary attitude (anatomical neutrality) of the hands and wrists. This requires a much more severe angle. Though other shaped gripping handles are available, since individuals differ in shoulder breadth, chest geometry, and joint limitations, a one-size-fits-all solution to an ideal gripping handle does not work.

BRIEF DESCRIPTION OF THE INVENTION

Embodiments of the present invention relate to a system and method for providing more effective use of a weight stack and anatomically correct body movement. In one exemplary embodiment, a system for controlling a free end of a stack pin used with a stack of weights is disclosed. The system comprises a nesting device configured to secure the free end of a stack pin when the stack pin is not lifting a weight and a tuning device configured to adjust the nesting device to exert a back up pressure on the stack pin to counteract potential energy that accumulates when the stack pin is being used to lift the weight.

Also disclosed is a system for reducing a build up of potential energy in a length of a stack pin used to lift a stack of weights where the system comprises at least two opposed stack-pin controllers, each controller comprises a base upon which two posts are mounted, between each pair of posts is a roller whose perimeter matches a radius of the stack pin, and a base of each controller which comprises a fastening device which allows for advancement or retraction of the controller to or from the stack pin to adjust a pressure applied to a free end of the stack pin by the rollers.

A method for reducing a buildup of potential energy in a length of a stack pin used with a stack of weights is also disclosed. The method comprises providing a stack pin with a top plate at a first end, locating at least two rollers on opposite sides of the stack pin at an end of the stack pin furthest away from the top plate into which the stack pin is nested, and adjusting the rollers to reduce backup pressure each time a selector pin is inserted and/or retracted which, in turn, prevents a buildup of a spring effect or potential energy in the length of the stack pin.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an illustration of a prior art representation of a selector pin being engaged with a weight in the selectorized weight stack;

FIG. 2 depicts an illustration of the prior art selectorized weight stack;

FIG. 3 depicts a prior art lower back (trunk extension) machine where a correct form is depicted showing the knees slightly flexed and the heels firmly planted on the pedestal;

FIG. 4 depicts a user violating the positioning shown in FIG. 3 by both straightening the legs and coming off the heels;

FIG. 5 depicts another prior art representation of a lower back machine;

FIG. 6 discloses a prior art embodiment of the pull down exercise machine;

FIG. 7 depicts an illustration of an exemplary embodiment of a weight-stack tuner;

FIG. 8 depicts an illustration of another exemplary embodiment of a weight-stack tuner;

FIG. 9A depicts an illustration of a side view of the weight-stack tuner with a stack pin in a nested position;

FIG. 9B depicts an illustration of a side view of the weight-stack tuner with the stack pin elevated from the weight-stack tuner;

FIG. 10 depicts a method for reducing a buildup of potential energy in a length of a stack pin;

FIG. 11 depicts an exemplary embodiment of a trunk extension machine;

FIG. 12 depicts a comparison of excursion between prior art machines and an exemplary embodiment of the present invention;

FIG. 13 discloses an exemplary embodiment of an adjustable pulling handle;

FIG. 14 discloses an exemplary embodiment of another view of the adjustable pulling handle where an adjustment gauge is visible;

FIG. 15 illustrates a top view of a uniformly adjustable wedge with a gauge.

DETAILED DESCRIPTION OF THE INVENTION

Reference will be made below in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals used throughout the drawings refer to the same or like parts. Exemplary embodiments of the invention solve problems in the art by providing control over a second end of a weight stack and providing components to allow for anatomically correct body movement during certain exercises.

Though exercise machines are disclosed herein when describing the invention, exemplary embodiments of the invention are applicable to other machines as well. For example, rehabilitation machines would also benefit from exemplary embodiments of the invention disclosed herein. Thus, the teaching of exemplary embodiments of the invention with respect to exercise machines shall not be considered limiting as they are applicable to other machines as well.

FIGS. 7 and 8 depict illustrations of an exemplary embodiment of a weight-stack tuner. The tuner 13 comprises two opposed stack-pin controllers 15, or controller mounts. Each controller comprises a base 39 upon which two pulley posts 40 are mounted. Between each pair of posts 40 is a roller, or wheel, 42 whose perimeter matches the radius of the stack pin 14. The base 39 of each controller 15 contains fastening slots 44 which allow a technician to advance or retract the controller 15 to or from the stack pin 14 and precisely secure it with fastening bolts, or fasteners, 45 to a mount below 17. Each wheel 42 has an opening through a centerpoint. A guide 50, which connects between the pair of posts 40, is positioned through the opening to receive the wheels 42 through each wheel's centerpoint.

The tuner 13 results in a system with adjustable rollers 42 that precisely abut the lower end of the guiderod and/or stack pin 14 as it nests between the rollers 42 at the lower end of the weight stack's stroke. Once adjusted correctly (tuned), it provides perfect, or preferred, backup pressure each time the selector pin 12 is inserted and/or retracted from between (or in) a weight plate 10, thus, preventing a buildup of a spring effect or potential energy in the length of the stack pin 14. No walking of the weight plates 10 occurs, and no choking of the guiderods 18 occurs.

FIG. 9A depicts an illustration of a side view of the weight-stack tuner 13 with the stack pin 14 in a nested position, and FIG. 9B depicts an illustration of a side view of the weight-stack tuner 13 with the stack pin 14 elevated from the weight-stack tuner 13. The back pressure provided by the tuner 13 is not needed once the selector pin 12 is trapped inside the weight stack 10 when under load.

Though the tuner 13 is depicted as having rollers 42 held in place by a pair of posts 40, other configurations of the tuner 13 is possible. For example, the tuner 13 can actually be considered two components, a tuner device and a nesting device. The nesting device is configured to contact the free end, or bottom end, of the stack pin 14. Based on the figures, the top end is not a free end since it has a weight 11 affixed to it. The configuration of the nesting device may actually be the rollers 42, which are used to transfer the potential energy stored in the stack pin away from the stack pin 14, or another device, a receiving device, which is also in contact with the free end of the stack pin 14 when the stack pin 14 is not being used to lift weight. Though the receiver is not expressly disclosed in the figures, the rollers 42 are representative of the receiving device. As essentially disclosed above, the tuning device is in essence the base 39, fastening slots 44, and fastening bolts 45, which allow the technician to advance or retract the nesting device 42 to an amount of pressure that would be applied by the nesting device 42 upon the stack pin 14 when in contact with the stack pin 14 when weight is not being lifted. Thus, the tuner is used to advance and retract the nesting device a distance where placement of the nesting device components can be viewed as defining an amount of pressure at which the nesting device contacts the stack pin when the stack pin is not being used to lift weight. Furthermore, though the rollers 42 are disclosed as being supported by posts, other configurations may be used, such as having the rollers 42 configured to attach directly to the base 39.

FIG. 10 depicts a method for reducing a buildup of potential energy in a length of a stack pin. The method, in flowchart 50 form, comprises providing a stack pin with a top plate at a first end, at 52. The method further comprises locating at least two pulley wheels on opposite sides of the stack pin at an end of the stack pin furthest away from the top plate into which the stack pin is nested, at 54. The method further comprises adjusting the pulley wheels to reduce backup pressure each time a selector pin is inserted and/or retracted which in turn prevents a buildup of a spring effect or potential energy in the length of the stack pin, at 56.

FIG. 11 depicts an exemplary embodiment of a trunk extension machine. As illustrated, the trunk extension machine puts the ankles and their extensional musculatures into active insufficiency where no clamping is necessary for controlling inappropriate heel raise or leg straightening. This is done with a heel wedge 60. Also disclosed are a hip-angled thigh constraint, or seatbelt, 62, a vertically-adjustable deck 64, a shin padding 66, a timing crank system 67, end-stop controls 68, and a height-adjustable seat 70. Note particularly the two Class-L rods 72 that serve as inner races for four linear bearings housed in aluminum blocks 74, 75. The upper block 74 and its bearings bear force horizontally toward the rear while the lower block 75 and its bearings bear force horizontally toward the front. (This avoids all vertical force on the aluminum blocks.) Thus, coupling contains the force applied to them from the weight of the platform, the weight of the subject and the force exerted by the subject into the movement arm of the machine. Also, the ACME-threaded rod 76 driven by the hand wheel 78 drives a flange nut that is levered upwards on the front of the coupled system to render the same and consistent force effect against the aluminum bearing blocks 74, 75.

The exemplary embodiment of the trunk extension machines comprises a seat 80 to supplant the saddle and pelvic buttress supplied on the Nautilus Lower Back® machine. As illustrated, the seat 80 is under the proximal thighs to permit full hip extension concurrent with spine extension. In this configuration, movement-arm range of motion to exceed the trunk is permitted. Optional extensional stops, to protect a user experiencing extensional limit issues, are provided. The timing crank system 67 is a crank-adjustable cam-timing system, or device, which may accommodate a user's variable endpoint resistance decrease requirements. The seat-belt 62 is provided to arrest reactionary forces at the hip angle in such a way as to not delimit extension. The weight-stack may be set with a gap at a desired amount to lift to delimit the flexional starting position for users who are flexionally limited.

A pedestal-height adjustment device is also provided. This is done with a uniquely coupled cantilevered design that permits adequate access and safe entry/exit and simultaneously enables precise and accurate positioning and repositioning without the user being required to step higher than 3.5 inches. Its design utilizes components and force to lift and hold the largest of users plus the force of effort against movement arm.

The wedge 60 is used to place the ankles into maximum extension. In one exemplary embodiment, the position of the wedge should accurately and precisely ensure repeatability by utilizing etched grids and non-skid between the wedge and the pedestal or base 61. Positioning into maximum ankle position solves two problems at once. First, it prevents the user from rising off the heels as the ankles are already run out as high as possible with depleted height potential. Second, maximum ankle extension locks the talus against the lower tibia and femur in the ankle to preclude leg (knee) straightening as the proximal thigh is constrained downward by the seat belt. Constraints around the calves may also be used to prevent knee straightening in subjects with feet issues which would disallow the use of the ankle wedge. Another feature that can be provided is a force-cell pickup with force-magnitude feedback via monitor to facilitate recordable and comparable performances of a timed-static contraction (isometric) exercise.

FIG. 12 depicts a comparison of excursion between prior art machines and an exemplary embodiment of the present invention. The top row depicts the MedX machine. The middle row depicts the Nautilus machine. The bottom row depicts an exemplary embodiment of the present invention. As illustrated, total excursion is greatest with the exemplary embodiment of the present invention. More particularly, the MedX® machine (“Prior Art A”) produces a total excursion of about 46.5 degrees whereas the Nautilus® machine (“Prior Art B”) produces a total excursion of about 98.5 degrees. The exemplary embodiment of the present invention provides a greater total excursion with a total excursion of about 122 degrees.

FIG. 13 discloses an exemplary embodiment of an adjustable pulling handle. The adjustable pulling handle 80 may be used with any exercise machine requiring such a handle. As illustrated, the handle 80 has a support bar 82. Grips 84 are angled for neutrality for a human hand and wrist, extending from the support bar 82. Ends of the grips 84 possess a keeper 86. The keeper 86 may be in a form of a disc, ball, and/or any suitable shape. The keeper 86 may be configured to allow for an optional and safe use of wrist hooks, attached to the grips 84, but not removed from the grips 84 by the keepers 86. The handle 80, or at least the grips 84, may be rubberized, such as by being covered with a rubberized material, for palm comfort.

Variable hand spacing is also achieved with the use of an opposing threaded rods 88,89, such as, but not limited to, ACME-threaded rods, that are welded and timed from a center of the support bar. One threaded rod 88 and its associated nut are right threaded while the other threaded rod 89 and nut are left threaded. The two threaded rods 88, 89 are fitted, connected, and/or fastened together at the center of the support bar 82 so that their nuts move either toward one another or away from one another at the same rate and distance as the threaded rods 88, 89 are rotated by a suitable hand crank 90 or knob from either end of the handle, or support bar.

Each angled grip 84 may be welded to its associated nut in a precise mirror image of the other. Each grip 84 moves with its nut 92 along the threaded rod 88 to a location (distance from the other) deemed best by the user. Its angle remains controlled with the square nut 92 as it traverses through a tube 93 within the support bar 82. As illustrated, the support bar 82 may be a square tube, with the tube being defined by the open area 94, or long slot(s) within the support bar 82. Each handle 84 emerges through a long slot 94 cut on a same side of the support bar 82. Both ends of the threaded rods 88, 89 are supported as they rotate by bushings mounted inside blocks, such as, but not limited to, steel blocks, which are fastened to each end of the tube, or support bar 82. Thus, when the hand crank 90 is turned, one of the threaded rods 88 will have a nut 92 which rotates in a clockwise rotation about the rod 88, hence moving its associated grip 84 in a first direction along the threaded rod 88. At the same time, the second threaded rod 89 will have a nut 92 which rotates in a counter-clockwise rotation about the rod 89, hence moving its associated grip 84 in a second direction along the threaded rod 89. Such a uniform movement allows for the grips 84 to remain equally spaced from the center of the support bar 82.

FIG. 14 discloses an exemplary embodiment of another view of the adjustable pulling handle where an adjustment gauge 97 is visible. Since others may use the exercise machine in between uses by a current user, the current user's ideal spacing may be identified on the adjustment gauge. The current user will then be able to quickly adjust the grips' configuration to the user's preference rather quickly as opposed to having to adjust the grips several times until a comfortable position is achieved each time the current user later uses the exercise machine.

Returning to the trunk extension machine illustrated in FIG. 11, FIG. 15 illustrates a top view of the wedge. As illustrated, placement of the wedge 60 may be adjustable, or, more specifically uniformly adjustable along a base 61 of the exercise machine to ensure repeated similar placement of the wedge. This is accomplished in part with an adjustment gauge 101 so that the user can return the wedge 60 to a predetermined position. The wedge 60 is uniformly adjusted with a combination of rods 88, 89 nuts 92, and a crank 90 as disclosed above with respect to the adjustable pulling handle 80. However, each nut 92 is connected to a respective extender 102 at a first end where the rods are connected together at a center location and are attached to the wedge 60 at a distal end. Thus, with respect to the wedge 60, when the hand crank 90 is turned, one of the threaded rods 88 will have a nut 92 which rotates in a clockwise rotation about the rod 88, hence moving an associated extender 102 in a first direction along the threaded rod 88. At the same time, the second threaded rod 89 has a nut 92 which rotates in a counter-clockwise rotation about the rod 89, hence moving its associated extender 102 in a second direction along the threaded rod 89. Such a uniform movement allows for both front corners 103 of the wedge 60 to remain equally spaced from the edges of a platform (meaning the wedge 60 is not transitioned to a skewed position with one corner extended further away from a front edge of a platform than the other). This mechanism also provides for the wedge 60 to remain stationary while an exercise is being performed. The application of opposing rods/nuts with respect to the wedge 60 is similar to the rods/nuts utilized with respect to the adjustable pull down handle.

Individually, in an exemplary embodiment a trunk extension system may comprise a seat configured to be positioned to permit full hip extension concurrent with spine extension, and a wedge device configured to position a user's ankles and extensional musculatures into active insufficiency wherein securing legs (or if the user has lost a leg, such as through amputation, legs shall mean a singular leg) of the user is unnecessary for controlling inappropriate heel raise and/or leg straightening. The system may further comprise a stack of weights wherein the lifting and lowering of the stack of weights is performed with a stack pin, the stack pin comprising a nesting device configured to secure a free end of a stack pin when the stack pin is not lifting an added amount of weight and a tuning device configured to adjust the nesting device to exert a pressure on the stack pin to counteract potential energy that accumulates when the stack pin is being used to lift the added amount of weight.

In another exemplary embodiment, a system for providing for a trunk extension exercise may comprise a seat configured to permit full hip extension concurrent with spine extension, a wedge device configured to put ankles of the user and their extensional musculatures into active insufficiency, a device configured to permit movement-arm range of motion to exceed the trunk, a crank-adjustable cam-timing to accommodate a user's variable endpoint resistance decrease requirements, a seatbelt to arrest reactionary forces at the hip angle to not delimit extension, a stack of weights where weight-stack gapping is provided to delimit a flexional starting position for a user who is flexionally limited, a seat height adjustment device, and a pedestal-height adjustment.

A exemplary embodiment of an adjustable pulling handle system may comprise a support bar, a first threaded rod and a second threaded rod, each threaded rod is located within the support bar, and connected together at adjacent ends, the first threaded rod having threads allowing for rotation of a nut in a first direction when the connected rods are rotated and the second threaded rod having threads allowing for rotation of a second nut in a second direction when the connected rods are rotated, a first grip and a second grip, each grip angularly extending from the support bar wherein the first grip is connected to the first nut and the second grip is connected to the second nut, and a crank attached to an end of one of the threaded rods to allow for the first nut to rotate in the first direction about its threaded rod when the crank is rotated and for the second nut to rotate in the second direction about its threaded rod when the crank is rotated. The grips may be equally spaced from a center of the support bar when rotation of the threaded rods is ceased, at any location along the length of the threaded rods.

In operation, the weight-stack tuner 13 may be used with any exercise machine and/or rehabilitation machine that utilize stacked weights. This includes trunk extension machines, leg extension machines, chest exercise machines, arm exercise machines (such as those requiring a pull handle), etc. Furthermore, a combination of all three components may be applicable to a single exercise machine and/or rehabilitation machine that may utilize stack weights, where a user's ankles and their extensional musculatures may need to be in active insufficiency (hence the use of the wedge 60), and where a pull handle may be needed, such as to assist the user entering and/or exiting the machine or where the machines is designed to allow performance of more than one type of exercise

While the invention has been described with reference to various exemplary embodiments, it will be understood by those skilled in the art that various changes, omissions and/or additions may be made and equivalents may be substituted for elements thereof without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated, any use of the terms first, second, etc., does not denote any order or importance, but rather the terms first, second, etc., are used to distinguish one element from another. 

1. A system for controlling a free end of a stack pin used with a stack of weights, the system comprising: a nesting device configured to secure the free end of a stack pin when the stack pin is not lifting a weight; and a tuning device configured to adjust the nesting device to exert a back up pressure on the stack pin to counteract potential energy that accumulates when the stack pin is being used to lift the weight.
 2. The system according to claim 1, wherein the nesting device comprises a pair of rollers configured to contact the free end of the stack pin when weight is not lifted.
 3. The system according to claim 1, wherein the nesting device comprises a receiver which is in contact with the free end of the stack pin when the stack pin is not being used to lift weight.
 4. The system according to claim 1, wherein the nesting device is configured to transfer potential energy stored in the stack pin away from the stack pin when the stack pin is not being used to lift weight.
 5. The system according to claim 1, wherein the nesting device is configured to exert a pressure on the stack pin to counteract potential energy accumulated in the stack pin.
 6. The system according to claim 1, wherein the tuning device is configured to advance and retract the nesting device a distance which defines an amount of pressure at which the nesting device contacts the stack pin when the stack pin is not being used to lift weight.
 7. The system according to claim 1, wherein the tuning device comprises a base, at least one fastening slot, and at least one fastener.
 8. The system according to claim 1, wherein the stack of weights and stack pin are part of an exercise machine and/or a rehabilitation machine.
 9. The system according to claim 8, further comprising the exercise machine and/or the rehabilitation machine comprising a wedge device configured to position a user's ankles and extensional musculatures into active insufficiency wherein securing legs of the user is unnecessary for controlling inappropriate heel raise and/or leg straightening.
 10. The system according to claim 8, further comprising the exercise machine and/or the rehabilitation machine comprising an adjustable pulling handle system.
 11. The system according to claim 10, wherein the adjustable pulling handle system comprises: a support bar; a first threaded rod and a second threaded rod, each threaded rod is located within the support bar and connected together at adjacent ends, the first threaded rod having threads allowing for rotation of a nut in a first direction when the connected rods are rotated and the second threaded rod having threads allowing for rotation of a second nut in a second, opposite, direction when the connected rods are rotated; a first grip and a second grip, each grip angularly extending from the support bar, the first grip is connected to the first nut and the second grip is connected to the second nut; and a crank attached to an end of one of the threaded rods to allow for the first nut to rotate in the first direction about its threaded rod when the crank is rotated and for the second nut to rotate in the second direction about its threaded rod when the crank is rotated.
 12. The system according to claim 1, wherein a gap is provided between the stack of weights to delimit a flexional starting position for a user who is flexionally limited.
 13. A system for reducing a build up of potential energy in a length of a stack pin used to lift a stack of weights, the system comprising at least two opposed stack-pin controllers, each controller comprises a base upon which two posts are mounted, between each pair of posts is a roller whose perimeter matches a radius of the stack pin, and a base of each controller which comprises a fastening device which allows for advancement or retraction of the controller to or from the stack pin to adjust a pressure applied to a free end of the stack pin by the rollers.
 14. The system according to claim 13, wherein the stack of weights are part of an exercise machine and/or a rehabilitation machine.
 15. The system according to claim 14, further comprising the exercise machine and/or the rehabilitation machine comprising a wedge device configured to position a user's ankles and extensional musculatures into active insufficiency wherein securing legs of the user is unnecessary for controlling inappropriate heel raise and/or leg straightening.
 16. The system according to claim 15, wherein the wedge device is configured to be uniformly adjustable along a base of the exercise machine and/or rehabilitation machine to ensure repeated similar placement of the wedge.
 17. The system according to claim 14, further comprising the exercise machine and/or the rehabilitation machine comprising an adjustable pulling handle system.
 18. The system according to claim 17, wherein the adjustable pulling handle system comprises: a support bar; a first threaded rod and a second threaded rod, each threaded rod is located within the support bar and connected together at adjacent ends, the first threaded rod having threads allowing for rotation of a nut in a first direction when the connected rods are rotated and the second threaded rod having threads allowing for rotation of a second nut in a second, opposite, direction when the connected rods are rotated; a first grip and a second grip, each grip angularly extending from the support bar, the first grip is connected to the first nut and the second grip is connected to the second nut; and a crank attached to an end of one of the threaded rods to allow for the first nut to rotate in the first direction about its threaded rod when the crank is rotated and for the second nut to rotate in the second direction about its threaded rod when the crank is rotated.
 19. The system according to claim 17, wherein the exercise machine and/or rehabilitation machine comprises a movement arm that permits movement-arm range of motion to exceed a trunk extension of a user.
 20. The system according to claim 17, wherein the exercise machine and/or rehabilitation machine comprises a crank-adjustable cam-timing device to accommodate a user's variable endpoint resistance decrease requirements.
 21. The system according to claim 13, wherein a gap is provided between the stack of weights to delimit a flexional starting position for a user who is flexionally limited.
 22. A method for reducing a build up of potential energy in a length of a stack pin used with a stack of weights, the method comprising: providing a stack pin with a top plate at a first end; locating at least two rollers on opposite sides of the stack pin at an end of the stack pin furthest away from the top plate into which the stack pin is nested; and adjusting the rollers to reduce backup pressure each time a selector pin is inserted and/or retracted which, in turn, prevents a buildup of a spring effect or potential energy in the length of the stack pin. 